Abstract : The fluent abstract machine supports a very powerful programming model. In addition to arbitrary access patterns, the instruction repertoire of the fluent machine also includes the multiprefix operation and high-level set operations. The fluent machine consists of over one hundred thousand processors interconnected by a butterfly network. The efficiency of the fluent machine derives from a very simple router, which effectively eliminates the possibility of congestion. The routing hardware is extremely simple inexpensive, and probably efficient.